diff options
Diffstat (limited to 'drivers/md/dm-cache-policy.h')
| -rw-r--r-- | drivers/md/dm-cache-policy.h | 33 |
1 files changed, 27 insertions, 6 deletions
diff --git a/drivers/md/dm-cache-policy.h b/drivers/md/dm-cache-policy.h index f0f51b26054..f50fe360c54 100644 --- a/drivers/md/dm-cache-policy.h +++ b/drivers/md/dm-cache-policy.h @@ -130,14 +130,11 @@ struct dm_cache_policy { * * Must not block. * - * Returns 1 iff in cache, 0 iff not, < 0 on error (-EWOULDBLOCK - * would be typical). + * Returns 0 if in cache, -ENOENT if not, < 0 for other errors + * (-EWOULDBLOCK would be typical). */ int (*lookup)(struct dm_cache_policy *p, dm_oblock_t oblock, dm_cblock_t *cblock); - /* - * oblock must be a mapped block. Must not block. - */ void (*set_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock); void (*clear_dirty)(struct dm_cache_policy *p, dm_oblock_t oblock); @@ -159,8 +156,24 @@ struct dm_cache_policy { void (*force_mapping)(struct dm_cache_policy *p, dm_oblock_t current_oblock, dm_oblock_t new_oblock); - int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock); + /* + * This is called via the invalidate_cblocks message. It is + * possible the particular cblock has already been removed due to a + * write io in passthrough mode. In which case this should return + * -ENODATA. + */ + int (*remove_cblock)(struct dm_cache_policy *p, dm_cblock_t cblock); + /* + * Provide a dirty block to be written back by the core target. + * + * Returns: + * + * 0 and @cblock,@oblock: block to write back provided + * + * -ENODATA: no dirty blocks available + */ + int (*writeback_work)(struct dm_cache_policy *p, dm_oblock_t *oblock, dm_cblock_t *cblock); /* * How full is the cache? @@ -196,6 +209,7 @@ struct dm_cache_policy { * We maintain a little register of the different policy types. */ #define CACHE_POLICY_NAME_SIZE 16 +#define CACHE_POLICY_VERSION_SIZE 3 struct dm_cache_policy_type { /* For use by the register code only. */ @@ -206,6 +220,13 @@ struct dm_cache_policy_type { * what gets passed on the target line to select your policy. */ char name[CACHE_POLICY_NAME_SIZE]; + unsigned version[CACHE_POLICY_VERSION_SIZE]; + + /* + * For use by an alias dm_cache_policy_type to point to the + * real dm_cache_policy_type. + */ + struct dm_cache_policy_type *real; /* * Policies may store a hint for each each cache block. |